Possible rod bearing? need NISTECH!

[0range_240]

So when I had my car in the garage the other day, I had just finished replacing my pulley, and I hd some time so I decided to yank the stock intake resonator out... since then tho Ive been noticing a funny rattling or knocking sound almost, when I give the car gas anywhere from 3000-4500 rpm .. .. its not very loud, and I have to turn off the heater and my radio to hear it.. but its unnerving

I took the car to a local shop and they said it was a rod bearing, and that I should rebuild my motor for 1800 bucks.... but firstly im not gonna pay that much if I can do a swap later, and secondly I dont know if they are just pulling my leg so they can do more work on the car.

Is there any definitive way, besides yanking the motor and checking, to tell if a rod bearing is gone? I tried listening with a stethescope, but the noise seems to be quite uniform all over the motor, with it being clearest over the #2 cylinder on the valve cover on the intake side... if it was a rod bearing, where should I place the stethescope to listen for it? and what should it sound like?

when I listened to the side of the block, the knock sounded very distance and muffled.. HELP

[NISTECH]

you can chase this to a specific cyl by pulling the plug wire out and rev it. if the noise goes away on one of your cyl's that is the cyl the noise is coming from. now weather its a rod bearing or piston slap its hard to tell. but the fact is you now no its a hard part in the engine which would require rebuilding. if the noise doesnt go away it is something other then poistons and rods causeing it.

[0range_240]

I took your advice and tried this, the noise is still there though thankfully (never thought id say that), so I can safely rule out the rod bearings or pistons?

It definitely does sound like mechanical knock, but not with much weight behind it.. ill say again though, because its so uncanny, that the noise sounds EXACTLY like a cold valvetrain... and also, I noticed that it DOESNT make the noise for the first few seconds of operation, and then after the RPM's have been bounced around 3000 or so for a second it quickly returns and stays

thanks for your help so far =)

[NISTECH]

maybe chain tensioner or chain slap? or is it something as simple as heat sheild rattle?

[0range_240]

heat shield has been removed, and I checked the timing chain tensioners and guides, and they are both there and in good condition.. how do you check if the chain is too loose?

I dont think its the chain though, because when I use a stethescope the sound is definitely coming from over or right around the #2 cylinder... atleast thats where the noise is clearest

[NISTECH]

check your rocker arms see if any are loose on the rocker shaft. It is even possible a lifter is dropping out.

[0range_240]

I pulley my rocker assembly and tried to check them, although I dont really know how to tell if a lifter has gone bad, or anything like that at all.. could someone explain how?

[NISTECH]

well you are the go getter. sorry I wasnt clearer you check the rockers while they are still installed on the car. sorry bout that. the lifters should be very difficult to push down if they are full of oil.

[0range_240]

I will check that tonight, also is it possible to start up the car briefly with the valve cover off to possibly listen to hear which one it is?

[NISTECH]

you'll have oil every where if you do that. it will end up on the fenders the hood.its up to you but dont let it run long cause it will be messy.